Various types of dispensers for fluent materials have been devised. For example, U.S. Pat. No. 3,560,100 discloses a roll-on applicator having a ball at the forward end thereof which rotates or rolls when moved against the surface to which the fluent material is to be applied to transfer the material from the ball to the desired surface (such as a portion of the human body, for example). The dispenser is provided with a cap and a spring-biased piston which, upon removal of the cap, is spring-biased to a position wherein it maintains a continuous pressure against the fluent material to be dispensed and applied.
U.S. Pat. No. 3,088,636 shows a fluent material dispenser (for toothpaste, for example) having a deformable head portion of a pliant, elastic material which, when despressed, will discharge the material to be dispensed through a discharge outlet. After dispensing a desired quantity of the fluent material, the discharge head is allowed to spring back to its initial shape, thereby producing a partial vacuum in the dispenser. Atmospheric pressure in the rear end of the dispenser will then force a one-way follower device in the dispenser chamber in a forward direction against the fluent material in the chamber, resulting in a decrease in the effective internal volume of the dispenser chamber.
Co-pending U.S. patent application No. 597,829, filed July 21, 1975, discloses a pump device for dispensing fluids. This pump device includes a cap which, when screwed onto the pump means, compresses a compression spring to store energy therein. Removal of the cap preparatory to use releases the energy stored in the compression spring to pressurize the fluid to be dispensed so that fluid can be sprayed upon operation of a dispensing actuator.